Microstructure induced nonlinearity of unconsolidated rocks as related to seismic diagnostic problems

Nonlinear Processes in Geophysics

V. Yu. Zaitsev¹  L. A. Ostrovsky¹  I. Yu. Belyaeva¹ 

[1] Institute of Applied Physics, Russian Academy of Sciences, 46 Uljanov Str., 603600 Nizhny Novogorod, Russia

Others  :  1006429
DOI  :  doi:10.5194/npg-4-1-1997

【 摘 要 】

Manifestationsofthe so-called structure inducednonlinearity are considered for thecase of a granularmedium,the latter being a generally acceptedmodel ofnonconsolidatedrocks inseismics. The considerationis carried outusing themediummodel intheform ofthe"ideal" random packing ofspherical elasticgranules inwhichthe interparticle spacecanbe filledwith afluid.A physicalequation of such amedium is derived; the dependencies ofnonlinearparameters onthe grainmaterial elasticmoduli, thefluidcompressibilityand theinitial medium strainare analyzed.Theinfluence ofdefects in nonideal grainpackings (that is, thepresence of afraction ofunloaded intergranularcontacts)upon thenonlinearproperties ofthemediumis investigated. Itisshown that the packingnonideality has thestrongereffect onhigher-order nonlinear properties. Itis demonstratedthat thenonlinear parameters maybe used in explorationseismologyasa much moresensitive and informative characteristic comparedwith conventionally used linear moduli.

【 授权许可】

   
© Author(s) 1997. This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 2.5 License.